1. Field of the Invention
The invention relates generally to structures for mounting an end of a rotary shaft of a mixing agitator in relation to an inner wall of a kettle within which materials are to be mixed or stirred, the structures of the invention providing a toe bearing mounting capability while allowing rapid disassembly for cleaning purposes.
2. Description of the Prior Art
The processing of many materials including pharmaceuticals, foodstuffs and the like on an industrial scale often requires mixing or stirring operations and, in some circumstances, the scraping of inner wall surfaces of a kettle within which materials are being mixed. Scraping of wall surfaces is particularly necessary in many situations involving the heating and/or cooking of food materials in large cooking kettles. Examples of mixing agitators which include a kettle wall scraping capability are disclosed in U.S. Pat. Nos. 3,752,057 to Groen, Jr.; 4,571,091 to Pardo et al and 4,790,667 to Pardo et al. The Pardo et al agitators include rotary shafts mounted within a kettle with the shaft disposed horizontally. Mounting of the Pardo et al horizontal agitators is readily accomplished through the use of bearing structure as is disclosed in the Pardo et al patents. That bearing structure described by Pardo et al allows rapid disassembly of the agitator structure and bearing structure such that daily cleaning can be easily accomplished. Groen, Jr., in U.S. Pat. No. 3,752,057 describes a mixing agitator having a shaft which extends into a kettle at an angle of at least 20.degree. with respect to the vertical axis of the kettle. The Groen, Jr. agitator is exemplary of an inclined agitator. However, many inclined agitators are configured with the inclined shafts thereof being mounted to a bearing located on an inner wall of a kettle so that the end of the inclined shaft extending into the kettle has a bearing support. Inclined agitators so configured can provide only stirring or mixing functions or can be fitted with scraping elements which allow scraping of wall surfaces of the kettle such as during a heating/cooking operation within the kettle. Certain other mixing agitators, some of which include scraping elements, are configured with the rotary shafts thereof disposed in a substantially vertical orientation with one end extending into the interior of a kettle or other container within which mixing operations occur. While vertically oriented agitators can be "held" by structure mounting the end of the agitator which is disposed outside of the kettle without contact, even through bearing surfaces, between inner walls of the kettle and that end of the shaft extending into the kettle, it is a common occurrence in the art to provide a bearing mounted to the inner wall of a kettle, such as at its lowermost location, so that the vertical shaft of the agitator can be mounted with at least the lower end of the agitator shaft within the kettle. Bearing structures of the prior art which are mounted to inner walls of a kettle for mounting inclined or vertical mixing agitators suffer from a number of disadvantages not the least of which is product standards which must be adhered to when metal to metal contact occurs within the body of food materials being processed. Such bearings must operate within proscriptions of law relating to the use of lubricants within the body of food materials being processed. Such bearing surfaces also must be formed of materials which comply with legal regulations involving metal to metal contact within the body of food materials being processed such as application of heat to the food materials during mixing, stirring and/or scraping of kettle wall surfaces. Prior art bearing structures also are generally not capable of repair due to the fact that the bearings are welded to inner walls of a kettle, excessive wear of the bearing or damage to the bearing thereby rendering the entire assembly useless.
The present invention provides a shaft toe mount useful with both inclined and vertical agitators in the processing of materials which can include the heating and/or cooking of food materials in a kettle either with or without scraping of inner walls of the kettle. The present shaft toe mount is configured to allow rapid removal from a kettle so that the mount as well as the kettle and agitator can be disassembled easily for cleaning on a daily basis according to accepted standards of cleanliness. The present shaft toe mount of the invention is formed of materials which meet USDA standards for metal to metal contact within a body of food materials being processed and in food processing situations where the use of lubricants is closely regulated. The present shaft toe mount of the invention can also be readily and rapidly repaired in the event of excessive wear or damage to the structure of the mount. Accordingly, the present invention provides substantial performance, operational and cost advantages over those bearing structures previously used in the art for the mounting of the rotary shaft of a mixing agitator structure used in a kettle for processing of materials including food materials, pharmaceuticals, and the like.